Design of Coltuximab Ravtansine, a CD19-Targeting Antibody Drug Conjugate (ADC) for the Treatment of B-Cell Malignancies: Structure-Activity Relationships and Preclinical Evaluation
Design of Coltuximab Ravtansine, a CD19-Targeting Antibody Drug Conjugate (ADC) for the Treatment of B-Cell Malignancies: Structure-Activity Relationships and Preclinical Evaluation
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DOI：
10.1021/acs.molpharmaceut.5b00175
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发表时间：
2015-06-01
影响因子：
4.9
通讯作者：
Lambert, John M.
中科院分区：
文献类型：
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作者：
Hong, E. Erica;Erickson, Hans;Lambert, John M.
Coltuximab ravtansine （SAR3419）是一种靶向CD19的抗体-药物偶联物（ADC），通过将强效微管作用细胞毒性药物美坦辛的衍生物与抗CD19抗体抗b4偶联而成，该抗体通过可变结构域重新表面修饰为IgG1人源化。我们合成了四种不同的连接体-类麦黄素（每一种连接体平均接近3.5个麦黄素/抗体），以评估连接体-有效载荷设计对靶向CD19的麦黄素- adc活性的影响。选择DM4 （N（2’）-去乙酰基-N（2’）-[4-巯基-4-甲基-1-氧戊基]美坦辛）通过N-琥珀酰酰-4-（2-吡啶双硫代）丁酸酯（SPDB）偶联抗体组成的ADC，开发为SAR3419。选择DM4/antibody的摩尔比为3 ~ 5作为SAR3419的最终设计。在Ramos肿瘤异种移植模型中对SAR3419的评估显示，最小有效单次剂量约为50 μ g/kg偶联DM4（类似于2.5 mg/kg偶联抗体），而在100%的小鼠中，该剂量的两倍完全回归。SAR3419在细胞周期的G2/M期阻滞细胞，最终在约24小时后导致细胞凋亡。在体外和体内的研究结果表明，在美丹素类C20甲氧基上[h -3]标记的DM4制造的SAR3419存在内化和细胞内运输机制，最终进入溶酶体，抗体在溶酶体中被完全降解，释放赖氨酸- n- epsilon- spdb -DM4作为初始代谢产物。随后，连接物和DM4之间的二硫键在细胞内还原产生游离硫醇，然后通过细胞甲基转移酶活性将其转化为s -甲基DM4。我们提供的证据表明，肿瘤细胞中s -甲基DM4的产生可能通过旁观者杀死邻近肿瘤细胞来促进体内肿瘤根除。此外，我们发现s -甲基DM4在肝脏中转化为亚砜和砜衍生物，这表明有效载荷的肝脏分解代谢为细胞毒性较小的美坦素类物质有助于SAR3419的整体治疗窗口。该化合物目前正处于治疗弥漫性大B细胞淋巴瘤的II期临床评估。
Coltuximab ravtansine (SAR3419) is an antibody-drug conjugate (ADC) targeting CD19 created by conjugating a derivative of the potent microtubule-acting cytotoxic agent, maytansine, to a version of the anti-CD19 antibody, anti-B4, that was humanized as an IgG1 by variable domain resurfacing. Four different linker-maytansinoid constructs were synthesized (average similar to 3.5 maytansinoids/antibody for each) to evaluate the impact of linker-payload design on the activity of the maytansinoid-ADCs targeting CD19. The ADC composed of DM4 (N(2')-deacetyl-N(2')-[4-mercapto-4-methyl-1-oxopentyl]maytansine) conjugated to antibody via the N-succinimidyl-4-(2-pyridyldithio)butyrate (SPDB) linker was selected for development as SAR3419. A molar ratio for DM4/antibody of between 3 and 5 was selected for the final design of SAR3419. Evaluation of SAR3419 in Ramos tumor xenograft models showed that the minimal effective single dose was about 50 mu g/kg conjugated DM4 (similar to 2.5 mg/kg conjugated antibody), while twice this dose gave complete regressions in 100% of the mice. SAR3419 arrests cells in the G2/M phase of the cell cycle, ultimately leading to apoptosis after about 24 h. The results of in vitro and in vivo studies with SAR3419 made with DM4 that was [H-3]-labeled at the C20 methoxy group of the maytansinoid suggest a mechanism of internalization and intracellular trafficking of SAR3419, ultimately to lysosomes, in which the antibody is fully degraded, releasing lysine-N-epsilon-SPDB-DM4 as the initial metabolite. Subsequent intracellular reduction of the disulfide bond between linker and DM4 generates the free thiol species, which is then converted to S-methyl DM4 by cellular methyl transferase activity. We provide evidence to suggest that generation of S-methyl DM4 in tumor cells may contribute to in vivo tumor eradication via bystander killing of neighboring tumor cells. Furthermore, we show that S-methyl DM4 is converted to the sulfoxide and sulfone derivatives in the liver, suggesting that hepatic catabolism of the payload to less cytotoxic maytansinoid species contributes to the overall therapeutic window of SAR3419. This compound is currently in phase II clinical evaluation for the treatment of diffuse large B cell lymphoma.